Which of the following statement is incorrect for Active Electronically Scanned Array Radar (AESA) ?

Correct — option (1), It is not capable of tracking multiple targets.

The stem asks for the incorrect statement. DRDO's product description of its Active Electronically Scanned Array (AESA) radar, developed by the Electronics & Radar Development Establishment (LRDE), settles each option.

Option (1), It is not capable of tracking multiple targets, contradicts that description. DRDO says the radar is capable of tracking multiple targets with high accuracy, suitable for firing missiles. So option (1) is the incorrect statement.

Option (2) matches: the listed features include a wide band RF front end.
Option (3) matches: DRDO calls it a multimode, solid-state active phased array fire control radar.
Option (4) matches: its scalable architecture can be adapted for various types of fighter class of aircraft.

The idea to remember: tracking multiple targets is a listed strength of the AESA radar, not a limitation.

Why the others are wrong

• (2)
  The radar features include wide band RF front end. — This statement is true, so it cannot be the incorrect one. DRDO lists a wide band RF front end first among the radar's features.

  The same list goes on to ultra low antenna side lobes, frequency and waveform agility, jammer suppression, Low Probability of Intercept and Non Co-operative Target Recognition.

• (3)
  It is solid-state active phased array fire control radar. — This statement is true. DRDO describes the radar as a multimode, solid-state active phased array fire control radar.

  'Active' means each element of the array has its own transmit/receive module. 'Fire control' means it supports weapons use — here, tracking targets accurately enough for firing missiles.

• (4)
  It can be adapted for various types of fighter class of aircraft. — This statement is true. DRDO says the radar has a scalable architecture that can be adapted for various types of fighter class of aircraft.

  It also offers interleaved Air to Air, Air to Ground and Air to Sea modes for all terrain operation.

A phased array radar steers its beam electronically, by adjusting the phase of signals across many antenna elements, instead of physically turning the antenna.

In an active electronically scanned array, each element has its own small solid-state transmit/receive module. In a passive electronically scanned array (PESA), one central transmitter feeds the elements through phase shifters.

With no antenna to swing round, an AESA can move its beam between directions very quickly. That helps it keep several targets in track and run modes such as air-to-air and air-to-ground interleaved.

Key facts

• DRDO's AESA radar is a multimode, solid-state active phased array fire control radar with scalable architecture, developed by LRDE.
• It can be adapted for various types of fighter class of aircraft.
• Listed features: wide band RF front end, ultra low antenna side lobes, frequency and waveform agility, jammer suppression, Low Probability of Intercept, Non Co-operative Target Recognition.
• It can track multiple targets with high accuracy, suitable for firing missiles, with interleaved Air to Air, Air to Ground and Air to Sea modes.
• In an AESA each array element has its own solid-state transmit/receive module; in a passive array one transmitter feeds the elements.

Common traps

• A single 'not' can turn a listed capability into a false statement while every technical term around it stays accurate. Check what the sentence claims the radar can or cannot do, not just its vocabulary.
• Active and passive phased arrays both steer beams electronically. 'Active' refers to a transmit/receive module at each element, not to the radar being switched on.
• Low Probability of Intercept is a feature that makes the radar's own emissions hard for others to detect. It does not mean the radar has trouble detecting targets.

UnlockIAS will link similar questions from RAS Pre 2023 here once that paper is published on this site.

• practice — not a real PYQ

  In an Active Electronically Scanned Array (AESA) radar, the beam is steered by –

  • (a)rotating the antenna mechanically
  • (b)electronically controlling signals across many transmit/receive modules
  • (c)moving a reflector dish
  • (d)changing the heading of the aircraft
  Answer(2) — An AESA steers its beam electronically, with a solid-state transmit/receive module at each element. Options (1) and (3) describe mechanical scanning, and option (4) moves the platform, not the beam.
• practice — not a real PYQ

  Consider the following features listed by DRDO for its AESA fire control radar : A. Jammer suppression B. Low Probability of Intercept C. Non Co-operative Target Recognition Which of the above are correct ?

  • (a)A and B only
  • (b)B and C only
  • (c)A and C only
  • (d)A, B and C
  Answer(4) — DRDO's feature list names all three, along with wide band RF front end, ultra low antenna side lobes and frequency and waveform agility. Options (1), (2) and (3) each leave out one listed feature.